ABSTRACT
Acuity for vertical, horizontal, and oblique gratings was measured in 77 infant astigmats using a preferential looking procedure. Measurements were made with the refractive error uncorrected. Most of the infant astigmats were slightly to moderately hyperopic with respect to the test distance of 50 cm. Their acuity was not significantly different from that of a group of non-astigmatic infants. Average acuity for vertical and horizontal gratings increased from 6/200 at 1 month of age to 6/24 at 1 yr. Average acuity for oblique gratings increased more slowly, so that by 1 yr of age it was only 6/33. The only infants to show reductions in acuity were those with a strong myopic focus and one infant with a very strong hyperopic focus. When this infant was tested with optical correction, acuity improved to normal levels. This suggests that meridional amblyopia develops sometime after the first year of life or that it is confined to high spatial frequencies.
Subject(s)
Astigmatism/physiopathology , Visual Acuity , Child, Preschool , Eye/physiopathology , Humans , Hyperopia/physiopathology , Infant , Infant, NewbornABSTRACT
Visual acuity and stereopsis of 19 esotropic infants and toddlers, 36 normal infants and 7 children with refractive anomalies were measured during the first three years of life using newly developed preferential looking procedures. Children with infantile esotropia corrected with prisms equal in size to the deviation show some degree of binocularity up to at least 21/2 years, as measured by a polaroid bar stereogram procedure with a 1800 seconds of arc disparity. A few children, who did not receive any therapeutic intervention, failed this test during the first and second year. However, all older subjects (over 6 years of age) with a history of infantile esotropia failed the test.
Subject(s)
Esotropia/physiopathology , Strabismus/physiopathology , Visual Acuity , Adolescent , Adult , Astigmatism/complications , Child , Child, Preschool , Esotropia/therapy , Female , Humans , Infant , Male , Middle Aged , Optics and PhotonicsABSTRACT
The orientation preferences of 70 infants aged 7 to 53 weeks with significant astigmatism [1.0 or more diopters (D)] were measured using a preferential looking procedure with paired gratings. The preference data show the consequences of the blurring effects of astigmatism when these are not compensatable by accommodation. Data from infant astigmats tested with optical correction look like those of nonastigmats. We have found no evidence for the development of meridional amblyopia during the first year of life.
Subject(s)
Amblyopia/physiopathology , Astigmatism/physiopathology , Accommodation, Ocular , Amblyopia/etiology , Astigmatism/complications , Fixation, Ocular , Humans , Infant , Pattern Recognition, Visual/physiology , Rotation , Visual AcuitySubject(s)
Albinism/physiopathology , Vision Tests/methods , Visual Acuity , Adult , Albinism/complications , Albinism/enzymology , Child, Preschool , Esotropia/complications , Female , Humans , Infant , Infant, Newborn , Male , Monophenol Monooxygenase/analysis , Nystagmus, Pathologic/complications , Vision Tests/instrumentationABSTRACT
Noncycloplegic refractions of 1,000 children aged 0-6 years revealed a high incidence of astigmatism, especially in the first 2 years of life. Before age 41/2 years, most of the astigmatism was against-the-rule and after that age most was with-the-rule. Of 19 children who did not show astigmatism in the first year, only one acquired it by 4 years. Of 29 children who had large amounts of astigmatism in the first year, all showed elimination or a large reduction in the amount of the cylindrical error by 4 years. These results are relevant to the etiology of astigmatism.
Subject(s)
Astigmatism/physiopathology , Refraction, Ocular , Age Factors , Astigmatism/epidemiology , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Vision, Ocular/physiologyABSTRACT
The measurement of visual acuity is an essential part of the eye examination of adults, but is rarely attempted in infants being examined for presumed or known eye disease. We have used a preferential looking technique to test visual acuity of infants attending a hospital eye clinic. Serial measurements of acuity of infants attending a hospital eye clinic. Serial measurements of acuity in infants with certain eye diseases can provide examples of the effects of visual deprivation on the developing human visual system. Amongst 14 cases of monocular visual form deprivation in early life, there were 9 infants who had monocular occlusion as therapy for esotropia; 3 infants who had unilateral opacities of the ocular media; and 2 infants who had unilateral eyelid closure from infection or burns. Despite differences in exact mode of deprivation, the effects on visual acuity were similar. There was a reduction of visual acuity in the deprived eye and a simultaneous increase in acuity of the non-deprived eye. These effects of monocular deprivation were not permanent. Recovery occurred with reverse deprivation or by simple cessation of the deprivation. Of 10 children with binocular visual form deprivation, there were 5 who had bilateral congenital cataracts and 5 who had bilateral uncorrected high refractive errors. Infants with cataract surgery before 2 months of age showed normal early development of visual acuity. A 4-6 month delay before treatment resulted in reduced acuity, but recovery subsequently occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Vision Disorders/diagnosis , Vision Tests/methods , Visual Acuity , Humans , Infant , Psychophysics , Sensory Deprivation , Vision Disorders/therapyABSTRACT
A preferential looking technique was used to measure visual acuity in human infants under one year of age who experienced monocular visual form deprivation. Of the 14 cases reviewed, 9 infants had monocular occlusion as therapy for esotropia; 3 infants had unilateral opacities of the ocular media; and 2 infants had unilateral eyelid closure from infection or burns. Despite differences in exact mode of deprivation, the effects on visual acuity were similar. There was a reduction in visual acuity in the deprived eye and a simultaneous increase in acuity of the non-deprived eye. These effects of monocular deprivation were not permanent. Recovery occurred with reverse deprivation or by simple cessation of the deprivation.
Subject(s)
Eye Diseases/complications , Form Perception , Vision Disorders/etiology , Visual Acuity , Cataract/complications , Esotropia/complications , Esotropia/therapy , Eyelid Diseases/complications , Humans , Infant , Orthoptics/methods , Vision Disorders/physiopathology , Vision Disorders/therapyABSTRACT
Visual acuity was measured with a preferential looking technique in infants and toddlers with binocular form deprivation. Of the 10 children in the study, there were 5 with congenital cataracts and 5 with uncorrected high refractive errors. Infants with cataract surgery before 2 months of age showed normal early development of visual acuity. A 4 to 6 month delay before treatment resulted in reduced acuity but recovery subsequently occurred. Infants with high hyperopia or astigmatism showed no acuity deficits in the first year of life when tested with optical correction. One case of early meridional amblyopia was detected in the third year of life. The deficit was not permanent and, after a period of optical correction, there was recovery of visual acuity to normal levels.
Subject(s)
Cataract/physiopathology , Form Perception , Refractive Errors/physiopathology , Visual Acuity , Age Factors , Astigmatism/physiopathology , Cataract Extraction , Child, Preschool , Humans , Infant , Vision Tests/methodsABSTRACT
We tested the visual acuities of 110 infants with ocular disorders by a preferential-looking technique that provides fast, accurate measurements for preverbal children. The results were used to confirm initial clinical evaluations and to prescribe and monitor treatment. The test was particularly helpful in assessing the effects of occlusion therapy. The child sat on a parent's lap 50 cm away from a black partition containing two circular screens. A grating was projected on one screen and a homogeneous field was projected on the other. A hidden observer watched the infant's eye and head movements to determine which screen was preferred.
Subject(s)
Eye Diseases/diagnosis , Vision Tests , Visual Acuity , Age Factors , Cataract/congenital , Coloboma/diagnosis , Corneal Injuries , Esotropia/diagnosis , Humans , Hydrocephalus/diagnosis , Infant , Infant, Newborn , Nystagmus, Pathologic/diagnosis , Optic Nerve/abnormalities , Optic Nerve Diseases/diagnosis , Strabismus/diagnosisABSTRACT
The visual acuity of 4 infants with congenital cataracts was measured serially during the first year of life by a preferential looking technique. Two infants with bilateral cataracts and no measurable acuity before surgery showed rapid development of acuity to normal levels for age after surgery and optical correction. In an infant with a unilateral cataract and an infant with a cataract and persistent hyperplastic primary vitreous marked differences in monocular acuities were found after surgery. Acuities became equal in the latter case after occlusion of the normal eye, while the other infant recovered acuity with 'bi-ocular' viewing. These acuity measurements demonstrate the sensitivity of the human visual system to binocular and monouclar visual form deprivation in the first year of life.
Subject(s)
Cataract/congenital , Child Development , Visual Acuity , Cataract Extraction , Depth Perception , Humans , Infant , Infant, Newborn , Sensory Deprivation , Visual PerceptionABSTRACT
Two experiments with adult subjects and one with infant subjects showed that the beam of a retinoscope, when viewed monocularly in a dark surround, does not stimulate accommodation. In this situation, the eye assumes an intermediate focus that is correlated with the individual's intermediate dark focus or resting state of accommodation. These results provide further evidence that near retinoscopy is a useful method of refraction which controls accommodation by minimizing effective stimulation. The technique is particularly valuable for refracting infants or young children who would otherwise require cycloplegia, and it may be an effective clinical method for the correction of night myopia and related anomalies in adults.
Subject(s)
Accommodation, Ocular , Photic Stimulation/instrumentation , Refraction, Ocular , Refractive Errors/diagnosis , Adult , Child, Preschool , Humans , Infant , Lasers , Middle Aged , Myopia/diagnosis , Myopia/therapy , Optometry/instrumentationABSTRACT
A simple and rapid method for assessing the visual acuity of infants can be a valuable tool for eye care specialists as well as for researchers in vision. We have developed a preferential looking (PL) procedure that uses simple equipment to obtain measures of PL acuity in a few minutes. Infants ranging in age from 2 weeks to 1 year can be tested. Sessions on infants without any visual problems are completed in less than 5 min. Computer simulations of the technique show that the fast procedure attains almost 80% accuracy in assessing infants' PL acuity thresholds. When PL acuity thresholds obtained by the 60-trial method of constant stimuli were compared to those obtained by the fast method on the same infants, they were identical on 70% of the sessions and only off by one-half octave in an additional 20% of the sessions. Interobserver reliability was also high. The ease and rapidity of the procedure make it appropriate for use in the clinic.
Subject(s)
Amblyopia/diagnosis , Vision Tests/methods , Visual Acuity , Age Factors , Amblyopia/complications , Astigmatism/complications , Cataract/complications , Computers , Humans , Infant , Infant, Newborn , Strabismus/complications , Vision Tests/instrumentationABSTRACT
The fast preferential looking procedure was used to obtain measures of acuity in a group of infants without visual problems whose ages spanned the 1st year of life. The results show an increase in acuity on horizontal and vertical square wave gratings from about 6/360 Snellen at 4 weeks of age to about 6/18 at 1 year. Acuity on obliquely oriented gratings (045) increases more slowly so that by 1 year of age it is only 6/36.
Subject(s)
Vision Tests/methods , Visual Acuity , Age Factors , Humans , Infant , Infant, Newborn , Vision Tests/instrumentationABSTRACT
Monocular acuities, in two infants with nonaccommodative comitant esotropia, were measured before and during occlusion therapy. The results indicate that strabismic amblyopia is present within the first year of life and that the infant visual system is remarkably sensitive to short periods of monocular occlusion during this time period.
Subject(s)
Amblyopia/etiology , Esotropia/complications , Strabismus/complications , Amblyopia/diagnosis , Amblyopia/therapy , Bandages , Critical Period, Psychological , Female , Humans , Infant , Male , Methods , Refraction, Ocular , Visual AcuityABSTRACT
New techniques have permitted serial assessments of visual acuity in infants. Acuity measurements in infants with astigmatism did not reveal meridional amblyopia during the first year of life. Measurements in infants with esotropia showed marked differences in acuity of the two eyes as early as the first 6 months of life. Therapeutic occlusion of the non-deviating eye improves the acuity of the deviating eye but at the expense of the occluded eye. After discontinuing occlusion, rapid increases in acuity of the formerly occluded eye can occur.
Subject(s)
Amblyopia/physiopathology , Aging , Amblyopia/etiology , Astigmatism/physiopathology , Cross-Sectional Studies , Esotropia/physiopathology , Esotropia/therapy , Humans , Infant , Longitudinal Studies , Visual AcuityABSTRACT
Retinoscopy under cycloplegia with various agents can yield varied results. Additionally, cycloplegics and produce adverse local as well as central nervous system disturbances. A noncycloplegic near retinoscopy technique as promulgated by Mohindra is compared with cycloplegic retinoscopy on schoolchildren in early grades. Results obtained by a study utilizing the two techniques show that they yield similar objective measurements of refraction.
Subject(s)
Mydriatics , Ophthalmoscopy/methods , Refraction, Ocular , Refractive Errors/diagnosis , Child , Child, Preschool , Humans , RetinaABSTRACT
Compared with children of school age, infants show ten times the incidence and considerably greater amounts of clinically significant astigmatism. The amount begins to decrease in the second semester of life, and the incidence declines during the third year. The unanticipated results bear on both the etiology and the neural sequelae of astigmatism.
Subject(s)
Astigmatism/epidemiology , Age Factors , Astigmatism/etiology , Astigmatism/physiopathology , Humans , Infant , Infant, Newborn , Infant, Newborn, Diseases/epidemiologyABSTRACT
A 4-year-old boy with uncorrected anisometropic indirect astigmatism showed amblyopia and strabismus. Over a period of approximately 3 yr, neutralization of the refractive error and treatment of the amblyopia and strabismus resulted in single binocular vision with good stereopsis. The results suggest that at least up to age 7 the visual system is sufficiently plastic to be modified by treatment.
